Fiber-reinforced plastic (FRP) has been used in general industrial structures and as structural materials for a wide range of fields such as aerospace and energy, due to its lightweight, high strength and high rigidity features.
While various characteristics are required for structural frameworks, it has recently become very important to develop a technology for suppressing or lowering vibrations among the above-described characteristics in terms of improvement of positional accuracy of structures and improvement in reliability of incorporated equipment.
However, the oscillation-damping characteristics of FRP is generally low, which is considerably inferior to that of metallic structures. Therefore, the present inventor developed a damping structure A (Fabric Engineering, Vol. 51, No. 3 (1998)) in which piezoelectric ceramics 5 and 6 are adhered to both sides of the outside of an FRP laminated structure 4 and a resistor 7 is connected between the respective piezoelectric ceramics 5 and 6 as shown in FIG. 3, in order to improve the oscillation-damping characteristics of FRP.
The presumed principle of damping using the piezoelectric ceramics is based on that, when an external force is applied to the piezoelectric ceramics, electric charge is generated by a piezoelectric effect, and electric energy is dissipated as Joule heat by causing the electric charge to pass through a resistor connected between the piezoelectric ceramics.
However, since it is necessary to connect a resistor to the outside of the above-described damping structure, there are disadvantages in terms of structure when such a damping structure is applied to practical applications provided with various molding processes.
The present invention was developed in view of the above-described problems and shortcomings, and it is therefore an object to provide a damping structure with simpler structure, which does not require connection of any resistor used for prior art damping structures and can be provided with various molding processes, and a damping base material for lamination which is a member of the above damping structure.